It is well known to heat crude oil and inject the stream into a fractionating tower having a side draw with which to extract a liquid product with a specified boiling range, flash point, and vapor pressure. As an example, the specified range of product from the crude oil stream may be that intermediate range entitled "diesel fuel". For analysis, that portion of the crude oil stream heavier than the diesel fuel is entitled "residual". The products lighter than the diesel fuel will be referred to as natural gasoline.
In further refinement of the diesel fuel product drawn from the fractionating tower, a second fractionating tower is provided in which steam stripping is used to closely control the desired boiling range, flash point, and vapor pressure of the diesel fuel as a final product.
It is becoming desirable to shift this relatively crude product separation into the field, closer to the wellhead. When this shift is made, it becomes highly desirable to eliminate the huge fractionation column of refinery practice, the second steam stripping column, and the source of steam. It is acceptable to provide additional equipment if the total capital output can be reduced.